Yeah, they need to find a different model. How many people are actually playing multiplayer? Most that I know setup their own dedicated server and play with friends or alone.

Your math has problems.
12x20 = 240 million revenue
So the server upkeep shouldn't be a problem with 6 million dollars a year.

It is just that out of the 240 million, in some countries VAT is included in the sale price so they have to pay that. So that's 200 million left. And out of that 30% goes to Steam. So 130 million left. They also have development (people), licensing, utilities etc. costs. So yeah, getting server costs under control will become important.